Plugins not working – Please help a WP newbie

I’m new to WordPress, so please bear with me…

I am running WordPress 3.0.4 on a hosted domain. I have successfully installed several plugins, but I am having problems with the following 3 that it was recommended I install:

1. Contact Form 7
2. FancyBox for WordPress
3. WP-PageNavi

The plugins I have installed and appear to work are:

1. Advanced Twitter Profile Widget
2. Akismet
3. All in One SEO Pack
4. Dean’s FCKEditor For WordPress
5. Google Analytics for WordPress
6. SexyBookmarks (by Shareaholic)
7. Social Media Widget
8. WordPress.com Stats

Does anyone see any incompatibilities, or is there something else I need to check? I am quite lost as this is my first day installing new plugins and most seemed to just plug in and run, but these three don’t seem to do anything.

Any and all help will be very much appreciated.

Thank you!